Electrophotographic imaging members with bichromophoric bisazo phthalocyanine photoconductive materials

ABSTRACT

Disclosed is an imaging member which comprises a conductive substrate and a photogenerating layer containing a compound selected from the group consisting of: ##STR1## and mixtures thereof, wherein Cp represents a coupler group, l, m, n, and o can each be 0, 1, 2, 3, or 4, the sum of l, m, n, and o is from 1 to 8, and M is selected from the group consisting of metals, metal oxides, metal halides, and metal hydroxy compounds.

BACKGROUND OF THE INVENTION

The present invention is directed to photoresponsive imaging members. More specifically, the present invention is directed to imaging members which contain photoconductive compounds with an azo moiety and a phthalocyanine moiety. One embodiment of the present invention is directed to an imaging member which comprises a conductive substrate and a photogenerating layer containing a compound selected from the group consisting of: ##STR2## and mixtures thereof, wherein Cp represents a coupler group, l, m, n, and o can each be 0, 1, 2, 3, or 4, the sum of l, m, n, and o is from 1 to 8, and M is selected from the group consisting of metals, metal oxides, metal halides, and metal hydroxy compounds.

Photoresponsive imaging members are known, such as those consisting of a homogeneous layer of a single material such as vitreous selenium, or composite layered devices containing a dispersion of a photoconductive composition. An example of a composite xerographic photoconductive member is described in U.S. Pat. No. 3,121,006, which discloses finely divided particles of a photoconductive inorganic compound dispersed in an electrically insulating organic resin binder. Imaging members prepared according to the teachings of this patent contain a binder layer with particles of zinc oxide uniformly dispersed therein coated on a paper backing. The binders disclosed in this patent include materials such as polycarbonate resins, polyester resins, polyamide resins, and the like, which are incapable of transporting injected charge carriers generated by the photoconductive particles for any significant distance. Accordingly, the photoconductive particles must be in a substantially contiguous particle to particle contact throughout the layer for the purpose of permitting the charge dissipation required for a cyclic operation.

Photoreceptor materials comprising inorganic or organic materials wherein the charge generating and charge transport functions are performed by discrete contiguous layers are also known. Additionally, layered photoreceptor members are disclosed in the prior art, including photoreceptors having an overcoat layer of an electrically insulating polymeric material. Other layered photoresponsive devices have been disclosed, including those comprising separate photogenerating layers and charge transport layers as described in U.S. Pat. No. 4,265,990, the disclosure of which is totally incorporated herein by reference. Photoresponsive materials containing a hole injecting layer overcoated with a hole transport layer, followed by an overcoating of a photogenerating layer, and a top coating of an insulating organic resin, are disclosed in U.S. Pat. No. 4,251,612, the disclosure of which is totally incorporated herein by reference. Examples of photogenerating layers disclosed in these patents include trigonal selenium and phthalocyanines, while examples of transport layers include certain aryl diamines as illustrated therein.

In addition, U.S. Pat. No. 3,041,167 discloses an overcoated imaging member containing a conductive substrate, a photoconductive layer, and an overcoating layer of an electrically insulating polymeric material. This member can be employed in electrophotographic imaging processes by initially charging the member with an electrostatic charge of a first polarity, followed by exposing it to form an electrostatic latent image that can subsequently be developed to form a visible image.

U.S. Pat. No. 3,574,181 discloses disazo compounds useful as coloring agents. Composite electrophotographic photosensitive materials containing various azo compounds are disclosed in U.S. Pat. No. 4,618,672, wherein bisazo compounds particularly suitable for use in the charge generating layer of a layered electrophotographic photoconductor are illustrated. Similarly, an article by M. Hashimoto entitled "Electrophotographic Sensitivity of Fluorenone Bisazo Pigments," Electrophotography, Vol. 25, No. 3 (1986), discloses disazo compounds as charge generating materials in electrophotographic layered photoreceptors. Further, Japanese Patent Kokai No. 54-20736 discloses disazo pigments as constituents in electrophotographic processes. Japanese Patent 58-177955 also discloses many disazo compounds suitable for use in the photosensitive layer of an electrophotographic device.

U.S. Pat. No. 4,713,307, the disclosure of which is hereby totally incorporated by reference, also discloses photoconductive imaging members containing a supporting substrate, certain azo pigments as photogenerating materials, and a hole transport layer that preferably contains an aryl diamine compound dispersed in an inactive resinous binder.

U.S. Pat. No. 4,797,337, the disclosure of which is totally incorporated herein by reference, discloses a photoconductive imaging member comprising a supporting substrate, a hole transport layer, and a photogenerating layer comprising specific disazo compounds.

Additional references illustrating layered organic electrophotographic photoconductor elements with azo, bisazo, and related compounds include U.S. Pat. No. 4,390,611, U.S. Pat. No. 4,551,404, U.S. Pat. No. 4,596,754, Japanese Patent 60-64354, U.S. Pat. No. 4,400,455, U.S. Pat. No. 4,390,608, U.S. Pat. No. 4,327,168, U.S. Pat. No. 4,299,896, U.S. Pat. No. 4,314,015, U.S. Pat. No. 4,486,522, U.S. Pat. No. 4,486,519, U.S. Pat. No. 4,555,667, U.S. Pat. No. 4,440,845, U.S. Pat. No. 4,486,800, U.S. Pat. No. 4,309,611, U.S. Pat. No. 4,418,133, U.S. Pat. No. 4,293,628, U.S. Pat. No. 4,427,753, U.S. Pat. No. 4,495,264, U.S. Pat. No. 4,359,513, U.S. Pat. No. 3,898,084, and Japanese Patent Publication 60-111247.

U.S. Pat. No. 4,755,443 discloses a photoreceptor for electrophotography which comprises a charge carrier generating material and charge transport material wherein one charge generating material is a metal phthalocyanine or a metal-free phthalocyanine. The layer containing the generator material also contains an organic amine. Other carrier generating substances can be used in combination with the phthalocyanine generator material, including azo pigments, anthraquinone dyes, perylene dyes, polycyclic quinone dyes, and methine stearate pigments.

U.S. Pat. No. 4,424,266 discloses an electrophotographic photosensitive element having a conductive support and a photosensitive layer comprising a carrier generating phase layer containing a carrier generating material selected from the group consisting of perylene dyes, polycyclic quinones, and azo dyes, and a carrier transporting phase layer containing a hydrazone carrier transporting material. The carrier generator materials can be used either singly or in combination.

U.S. Pat. No. 4,882,254, the disclosure of which is totally incorporated herein by reference, discloses a layered photoresponsive imaging member which comprises a supporting substrate, a photogenerator layer comprising a mixture of first and second pigments, and an aryl amine hole transport layer. The mixture of pigments is selected from perylenes and phthalocyanines, polycyclic quinones and phthalocyanines, or perinones and phthalocyanines.

Japanese Patent Publication J01-198-763 discloses an electrophotographic photoreceptor containing a bisazo series compound in a photosensitive layer formed on a conductive support. A charge transport material is used with the bisazo pigment as a charge generation material, such as 2,4,7-trinitrofluorenone, tetracyanoquinodimethane, carbazole, triarylalkane derivatives, phenylenediamine derivatives, hydrazone compounds, or stilbene derivatives.

Photoresponsive imaging members containing perinone and perylene compounds are also known. For example, European Patent Publication 0040402, DE3019326, filed May 21, 1980, discloses the use of N,N'-disubstituted perylene-3,4,9,10-tetracarboxyldiimide pigments as photoconductive substances. Specifically, there is disclosed in this publication evaporated N,N'-bis(3-methoxypropyl)perylene-3,4,9,10-tetracarboxyldiimide dual layered negatively charged photoreceptors with improved spectral response in the wavelength region of 400 to 700 nanometers. A similar disclosure is contained in Ernst Gunther Schlosser, Journal of Applied Photographic Engineering, Vol. 4, No. 3, page 118 (1978). Further, U.S. Pat. No. 3,871,882 discloses photoconductive substances comprising specific perylene-3,4,9,10-tetracarboxylic acid derivative dyestuffs. According to the teachings of this patent, the photoconductive layer is preferably formed by vapor depositing the dyestuff in a vacuum. This patent discloses dual layer photoreceptors with perylene-3,4,9,10-tetracarboxylic acid diimide derivatives, which have spectral response in the wavelength region of from 400 to 600 nanometers. Additionally, U.S. Pat. No. 3,879,200 discloses imaging members with perinones. Furthermore, layered imaging members with imidazole thiazinoperinone photogenerators and related components are illustrated in U.S. Pat. No. 4,517,270 and in Japanese Laid Open Publications 59-58433/84 and 59-59692/84.

U.S. Pat. No. 4,808,506, the disclosure of which is totally incorporated herein by reference, discloses a layered photoresponsive imaging member which comprises a supporting substrate, an imidazole perinone comprising components with a mixture of cis and trans isomers of a specific formula, including trans indanthrene Brilliant Orange, cis indanthrene Bordeauxs Red, bis-(4,5-dimethyl)benzimidazole perinone and bis-2,3-naphthimidazole perinone, and an aryl amine hole transport layer.

U.S. Pat. No. 4,587,189, the disclosure of which is totally incorporated herein by reference, discloses a photoresponsive imaging member comprising a supporting substrate, a vacuum evaporated photogenerator layer which comprises a perylene pigment.

Imaging members with phthalocyanine materials are also known, as disclosed in, for example, U.S. Pat. No. 3,594,163, U.S. Pat. No. 3,657,272, U.S. Pat. No. 3,816,118, U.S. Pat. No. 3,862,127, U.S. Pat. No. 3,903,107, U.S. Pat. No. 3,927,026, U.S. Pat. No. 3,932,180, U.S. Pat. No. 3,932,454, U.S. Pat. No. 4,031,109, U.S. Pat. No. 4,098,795, and U.S. Pat. No. Re. 27,117, the disclosures of each of which are totally incorporated herein by reference.

Of background interest is U.S. Pat. No. 4,868,079, which discloses an electrophotoconductor comprising a conductive support and a photoconductive layer comprising a resin binder having dispersed therein an anthranthrone compound, a phthalocyanine compound, and an oxadiazole compound.

Although known imaging members are suitable for their intended purposes, a need remains for imaging members containing bichromophoric photoconductive materials. In addition, a need exists for imaging members containing photoconductive materials with improved photoconductivity. Further, there is a need for imaging members containing photoconductive materials having azo moieties wherein the hole transporting and electron transporting mobility of the azo material is enhanced. There is also a need for imaging members containing photoconductive materials having azo moieties and a phthalocyanine moiety wherein the material has enhanced dispersability in polymers and solvents. Additionally, a need remains for imaging members containing photoconductive materials wherein the optical absorption of the material is increased. A need also remains for photoconductive materials having increased optical absorption, thereby enabling the use of reduced amounts of photoconductive material in an imaging member charge generating layer and thus improving electrical and environmental stability of the member. Further, there is a need for photoconductive materials with enhanced dispersability in polymers and solvents that enable low cost coating processes in the manufacture of photoconductive imaging members. In addition, there is a need for photoconductive materials and imaging members sensitive to light in the LED region (from about 660 to about 680 nanometers). There is also a need for photoconductive materials and imaging members sensitive to light in the diode laser region (from about 780 to about 840 nanometers).

SUMMARY OF THE INVENTION

It is an object of the present invention to provide imaging members containing bichromorphic photoconductive materials.

It is another object of the present invention to provide imaging members containing photoconductive materials with improved photoconductivity.

It is yet another object of the present invention to provide imaging members containing photoconductive materials having azo moieties wherein the hole transporting and electron transporting mobility of the azo material is enhanced.

It is still another object of the present invention to provide imaging members containing photoconductive materials having azo moieties and a phthalocyanine moiety wherein the material has enhanced dispersability in polymers and solvents.

Another object of the present invention is to provide imaging members containing photoconductive materials wherein the optical absorption of the material is increased.

Yet another object of the present invention is to provide photoconductive materials having increased optical absorption, thereby enabling the use of reduced amounts of photoconductive material in an imaging member charge generating layer and thus improving electrical and environmental stability of the member.

Still another object of the present invention is to provide photoconductive materials with enhanced dispersability in polymers and solvents that enable low cost coating processes in the manufacture of photoconductive imaging members.

It is another object of the present invention to provide photoconductive materials and imaging members sensitive to light in the LED region (from about 660 to about 680 nanometers).

It is yet another object of the present invention to provide photoconductive materials and imaging members sensitive to light in the diode laser region (from about 780 to about 840 nanometers).

These and other objects of the present invention are achieved by providing an imaging member which comprises a conductive substrate and a photogenerating layer containing a compound selected from the group consisting of: ##STR3## and mixtures thereof, wherein Cp represents a coupler group, l, m, n, and o can each be 0, 1, 2, 3, or 4, the sum of l, m, n, and o is from 1 to 8, and M is selected from the group consisting of metals, metal oxides, metal halides, and metal hydroxy compounds.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1, 2, 3, and 4 are schematic cross-sectional views of examples of photoconductive imaging members of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates schematically one embodiment of the imaging members of the present invention. Specifically, FIG. 1 shows a photoconductive imaging member comprising a conductive substrate 1, a photogenerating layer 3 comprising a bichromophoric photogenerating compound 2 selected from the group consisting of those compounds represented by Formulae I and II or mixtures thereof optionally dispersed in a resinous binder composition 4, and a charge transport layer 5, which comprises a hole transporting molecule dispersed in an inactive resinous binder composition 9.

FIG. 2 illustrates schematically essentially the same member as that shown in FIG. 1 with the exception that the hole transport layer is situated between the conductive substrate and the photogenerating layer. More specifically, this Figure illustrates a photoconductive imaging member comprising a conductive substrate 21, a hole transport layer 23 comprising a hole transport composition dispersed in an inactive resinous binder composition 25, and a photogenerating layer 27 comprising a bichromophoric photogenerating compound 28 selected from the group consisting of those compounds represented by Formulae I and II or mixtures thereof optionally dispersed in a resinous binder composition 29.

FIG. 3 illustrates schematically a photoconductive imaging member of the present invention comprising a conductive substrate 31, a hole blocking metal oxide layer 33, an optional adhesive layer 35, a photogenerating layer 37 comprising a bichromophoric photogenerating compound selected from the group consisting of those compounds represented by Formulae I and II or mixtures thereof optionally dispersed in a resinous binder composition; and an aryl amine hole transport layer 39 comprising an aryl amine hole transport compound optionally dispersed in a resinous binder.

FIG. 4 illustrates schematically a photoconductive imaging member of the present invention comprising a conductive substrate 41 and a photogenerating layer 43 comprising a bichromophoric photogenerating compound 42 selected from the group consisting of those compounds represented by Formulae I and II or mixtures thereof optionally dispersed in a resinous binder composition 44.

The substrate can be formulated entirely of an electrically conductive material, or it can be an insulating material having an electrically conductive surface. The substrate is of an effective thickness, generally up to about 100 mils, and preferably from about 1 to about 50 mils, although the thickness can be outside of this range. The thickness of the substrate layer depends on many factors, including economic and mechanical considerations. Thus, this layer may be of substantial thickness, for example over 100 mils, or of minimal thickness provided that there are no adverse effects on the system. In a particularly preferred embodiment, the thickness of this layer is from about 3 mils to about 10 mils. The substrate can be opaque or substantially transparent and can comprise numerous suitable materials having the desired mechanical properties. The entire substrate can comprise the same material as that in the electrically conductive surface or the electrically conductive surface can merely be a coating on the substrate. Any suitable electrically conductive material can be employed. Typical electrically conductive materials include copper, brass, nickel, zinc, chromium, stainless steel, conductive plastics and rubbers, aluminum, semitransparent aluminum, steel, cadmium, silver, gold, paper rendered conductive by the inclusion of a suitable material therein or through conditioning in a humid atmosphere to ensure the presence of sufficient water content to render the material conductive, indium, tin, metal oxides, including tin oxide and indium tin oxide, and the like. The substrate layer can vary in thickness over substantially wide ranges depending on the desired use of the electrophotoconductive member. Generally, the conductive layer ranges in thickness from about 50 Angstroms to many centimeters, although the thickness can be outside of this range. When a flexible electrophotographic imaging member is desired, the thickness typically is from about 100 Angstroms to about 750 Angstroms. The substrate can be of any other conventional material, including organic and inorganic materials. Typical substrate materials include insulating non-conducting materials such as various resins known for this purpose including polycarbonates, polyamides, polyurethanes, paper, glass, plastic, polyesters such as Mylar® (available from Du Pont) or Melinex 447 (available from ICI Americas, Inc.), and the like. If desired, a conductive substrate can be coated onto an insulating material. In addition, the substrate can comprise a metallized plastic, such as titanized or aluminized Mylar®, wherein the metallized surface is in contact with the photogenerating layer or any other layer situated between the substrate and the photogenerating layer. The coated or uncoated substrate can be flexible or rigid, and can have any number of configurations, such as a plate, a cylindrical drum, a scroll, an endless flexible belt, or the like. The outer surface of the substrate preferably comprises a metal oxide such as aluminum oxide, nickel oxide, titanium oxide, and the like.

In some cases, intermediate adhesive layers between the substrate and subsequently applied layers may be desirable to improve adhesion. If such adhesive layers are utilized, they preferably have a dry thickness of from about 0.1 micron to about 5 microns, although the thickness can be outside of this range. Typical adhesive layers include film-forming polymers such as polyester, polyvinylbutyral, polyvinylpyrolidone, polycarbonate, polyurethane, polymethylmethacrylate, and the like as well as mixtures thereof. Since the surface of the substrate can be a metal oxide layer or an adhesive layer, the expression "substrate" as employed herein is intended to include a metal oxide layer with or without an adhesive layer on a metal oxide layer.

The photogenerating layer contains a bichromophoric photogenerating compound of Formulae I or II or a mixture of two or more compounds of these formulae. Generally, this layer has a thickness of from about 0.05 micron to about 10 microns or more, and preferably has a thickness of from about 0.1 micron to about 3 microns. The thickness of this layer, however, is dependent primarily upon the concentration of photogenerating material in the layer, which may generally vary from about 5 to 100 percent. When the photogenerating material is present in a binder material, the binder preferably contains from about 30 to about 95 percent by weight of the photogenerating material, and preferably contains about 80 percent by weight of the photogenerating material. Generally, it is desirable to provide this layer in a thickness sufficient to absorb about 90 percent or more of the incident radiation which is directed upon it in the imagewise or printing exposure step. The maximum thickness of this layer is dependent primarily upon factors such as mechanical considerations, such as the specific photogenerating compound selected, the thickness of the other layers, and whether a flexible photoconductive imaging member is desired.

When present, the optional charge transport layer can comprise any suitable charge transport material. Examples of charge transport materials include pure selenium, selenium-arsenic alloys, selenium-arsenic-halogen alloys, selenium-halogen, and the like. Generally, from about 10 parts by weight per million to about 200 parts by weight per million of halogen dare present in a halogen doped selenium charge transport layer, although the amount can be outside of this range. If a halogen doped transport layer free of arsenic is utilized, the halogen content preferably is less than about 20 parts by weight per million. Transport layers are well known in the art. Typical transport layers are described, for example, in U.S. Pat. No. 4,609,605 and in U.S. Pat. No. 4,297,424, the disclosures of each of these patents being totally incorporated herein by reference.

Organic charge transport materials can also be employed. Typical charge transporting materials include the following:

Diamine transport molecules of the type described in U.S. Pat. Nos. 4,306,008; 4,304,829; 4,233,384; 4,115,116; 4,299,897 and 4,081,274, the disclosures of each of which are totally incorporated herein by reference. Typical diamine transport molecules include N,N'-diphenyl-N,N'-bis(3"-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine,N,N'-diphenyl-N,N'-bis(4-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-diphenyl-N,N'-bis(2-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-diphenyl-N,N'-bis(3-ethylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-diphenyl-N,N'-bis(4-ethylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-diphenyl-N,N'-bis(4-n-butylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-diphenyl-N,N'-bis(3-chlorophenyl)-[1,1'-biphenyl]-4,4'-diamine, N,N'-diphenyl-N,N'-bis(4-chlorophenyl)-[1,1'-biphenyl]-4,4'-diamine, N,N'-diphenyl-N,N'-bis(phenylmethyl)-[1,1'-biphenyl]-4,4'-diamine,N,N,N',N'-tetraphenyl-[2,2'-dimethyl-1,1'-biphenyl]-4,4'-diamine, N,N,N',N'-tetra-(4-methylphenyl)-[2,2'-dimethyl-1,1'-biphenyl]-4,4'-diamine, N,N'-diphenyl-N,N'-bis(4-methylphenyl)-[2,2'-dimethyl-1,1'-biphenyl]-4,4'-diamine, N,N'-diphenyl-N,N'-bis(2-methylphenyl)-[2,2'-dimethyl-1,1'-biphenyl]-4,4'-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[2,2'-dimethyl-1,1'-biphenyl]-4,4'-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-pyrenyl-1,6-diamine, and the like.

Pyrazoline transport molecules as disclosed in U.S. Pat. Nos. 4,315,982; 4,278,746 and 3,837,851, the disclosures of each of which are totally incorporated herein by reference. Typical pyrazoline transport molecules include 1-[lepidyl-(2)]-3-(p-diethylaminophenyl)-5-(p-diethylaminophenyl)pyrazoline, 1-[quinolyl-(2)]-3-(p-diethylaminophenyl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl-(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[6-methoxypyridyl-(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-phenyl-3-[p-dimethylaminostyryl]-5-(p-dimethylaminostyryl)pyrazoline, 1-phenyl-3-[p-diethylaminostyryl]-5-(p-diethylaminostyryl)pyrazoline, and the like.

Substituted fluorene charge transport molecules as described in U.S. Pat. No. 4,245,021, the disclosure of which is totally incorporated herein by reference. Typical fluorene charge transport molecules include 9-(4'-dimethylaminobenzylidene)fluorene, 9-(4'-methoxybenzylidene)fluorene, 9-(2',4'-dimethoxylbenzylidene)fluorene, 2-nitro-9-benzylidene-fluorene, 2-nitro-9-(4'-diethylaminobenzylidene)fluorene, and the like.

Oxadiazole transport molecules such as 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole, pyrazoline, imidazole, triazole, and the like. Other typical oxadiazole transport molecules are described, for example, in German Patents 1,058,836; 1,060,260 and 1,120,875, the disclosures of each of which are totally incorporated herein by reference.

Hydrazone transport molecules, such as p-diethylaminobenzaldehyde-(diphenylhydrazone), o-ethoxy-p-diethylaminobenzaldehyde-(diphenylhydrazone), o-methyl-p-diethylaminobenzaldehyde-(diphenylhydrazone), o-methyl-p-dimethylaminobenzaldehyde-(diphenylhydrazone), 1-naphthalenecarbaldehyde 1-methyl-1-phenylhydrazone, 1-naphthalenecarbaldehyde 1,1-phenylhydrazone, 4-methoxynaphthlene-1-carbaldehyde 1-methyl-1-phenylhydrazone, and the like. Other typical hydrazone transport molecules are described, for example, in U.S. Pat. Nos. 4,150,987; 4,385,106; 4,338,388 and 4,387,147, the disclosures of each of which are totally incorporated herein by reference.

Carbazole phenyl hydrazone transport molecules such as 9-methylcarbazole-3-carbaldehyde-1,1-diphenylhydrazone, 9-ethylcarbazole-3-carbaldehyde-1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-carbaldehyde-1-ethyl-1-phenylhydrazone, 9-ethylcarbazole-3-carbaldehyde-1-ethyl-1-benzyl-1-phenylhydrazone, 9-ethylcarbazole-3-carbaldehyde-1,1-diphenylhydrazone, and the like. Other typical carbazole phenyl hydrazone transport molecules are described, for example, in U.S. Pat. Nos. 4,256,821 and 4,297,426, the disclosures of each of which are totally incorporated herein by reference.

Vinyl-aromatic polymers such as polyvinyl anthracene, polyacenaphthylene; formaldehyde condensation products with various aromatics such as condensates of formaldehyde and 3-bromopyrene; 2,4,7-trinitrofluorenone, and 3,6-dinitro-N-t-butylnaphthalimide as described, for example, in U.S. Pat. No. 3,972,717, the disclosure of which is totally incorporated herein by reference.

Oxadiazole derivatives such as 2,5-bis(p-diethylaminophenyl)oxadiazole-1,3,4 described in U.S. Pat. No. 3,895,944, the disclosure of which is totally incorporated herein by reference.

Tri-substituted methanes such as alkyl-bis(N,N-dialkylaminoaryl)methane, cycloalkyl-bis(N,N-dialkylaminoaryl)methane, and cycloalkenyl-bis(N,N-dialkylaminoaryl)methane as described in U.S. Pat. No. 3,820,989, the disclosure of which is totally incorporated herein by reference.

9-Fluorenylidene methane derivatives having the formula ##STR4## wherein X and Y are cyano groups or alkoxycarbonyl groups, A, B, and W are electron withdrawing groups independently selected from the group consisting of acyl, alkoxycarbonyl, nitro, alkylaminocarbonyl, and derivatives thereof, m is a number of from 0 to 2, and n is the number 0 or 1 as described in U.S. Pat. No. 4,474,865, the disclosure of which is totally incorporated herein by reference. Typical 9-fluorenylidene methane derivatives encompassed by the above formula include (4-n-butoxycarbonyl-9-fluorenylidene)malononitrile, (4-phenethoxycarbonyl-9-fluorenylidene)malononitrile, (4-carbitoxy-9-fluorenylidene)malononitrile, (4-n-butoxycarbonyl-2,7-dinitro-9-fluorenylidene)malonate, and the like.

Other charge transport materials include poly-1-vinylpyrene, poly-9-vinylanthracene, poly-9-(4-pentenyl)-carbazole, poly-9-(5-hexyl)-carbazole, polymethylene pyrene, poly-1-(pyrenyl)-butadiene, polymers such as alkyl, nitro, amino, halogen, and hydroxy substitute polymers such as poly-3-amino carbazole, 1,3-dibromo-poly-N-vinyl carbazole, 3,6-dibromo-poly-N-vinyl carbazole, and numerous other transparent organic polymeric or non-polymeric transport materials as described in U.S. Pat. No. 3,870,516, the disclosure of which is totally incorporated herein by reference.

A particularly preferred charge transport molecule is one having the general formula ##STR5## wherein X, Y and Z are selected from the group consisting of hydrogen, an alkyl group having from 1 to about 20 carbon atoms and chlorine, and at least one of X, Y and Z is independently selected to be an alkyl group having from 1 to about 20 carbon atoms or chlorine. If Y and Z are hydrogen, the compound may be named N,N'-diphenyl-N,N'-bis(alkylphenyl)-[1,1'-biphenyl]-4,4'-diamine wherein the alkyl is, for example, methyl, ethyl, propyl, n-butyl, or the like, or the compound may be N,N'-diphenyl-N,N'-bis(chlorophenyl)-[1,1'-biphenyl]-4,4'-diamine.

The charge transport material is present in the charge transport layer in an effective amount, generally from about 5 to about 90 percent by weight, preferably from about 20 to about 75 percent by weight, and more preferably from about 30 to about 60 percent by weight, although the amount can be outside of this range.

Examples of the highly insulating and transparent resinous components or inactive binder resinous material for the transport layers include materials such as those described in U.S. Pat. No. 3,121,006, the disclosure of which is totally incorporated herein by reference. Specific examples of suitable organic resinous materials include polycarbonates, arcylate polymers, vinyl polymers, cellulose polymers, polyesters, polysiloxanes, polyamides, polyurethanes, polystyrenes, and epoxies as well as block, random or alternating copolymers thereof. Preferred electrically inactive binder materials are polycarbonate resins having a molecular weight of from about 20,000 to about 100,000 with a molecular weight in the range of from about 50,000 to about 100,000 being particularly preferred. Generally, the resinous binder contains from about 5 to about 90 percent by weight of the active material corresponding to the foregoing formula, and preferably from about 20 percent to about 75 percent of this material.

Similar binder materials may be selected for the photogenerating layer, including polyesters, polyvinyl butyrals, polycarbonates, polyvinyl formals, and those illustrated in U.S. Pat. No. 3,121,006, the disclosure of which is totally incorporated herein by reference. A preferred class of binder material for the photogenerating layer is a poly(vinyl acetal).

The photoconductive imaging member may optionally contain a charge blocking layer situated between the conductive substrate and the photogenerating layer. This layer may comprise metal oxides, such as aluminum oxide and the like, or materials such as silanes and nylons. Additional examples of suitable materials include polyisobutyl methacrylate, copolymers of styrene and acrylates such as styrene/n-butyl methacrylate, copolymers of styrene and vinyl toluene, polycarbonates, alkyl substituted polystyrenes, styrene-olefin copolymers, polyesters, polyurethanes, polyterpenes, silicone elastomers, mixtures thereof, copolymers thereof, and the like. The primary purpose of this layer is to prevent charge injection from the substrate during and after charging. This layer is of a thickness of less than 50 Angstroms to about 10 microns, preferably being no more than about 2 microns.

In addition, the photoconductive imaging member may also optionally contain an adhesive interface layer situated between the hole blocking layer and the photogenerating layer. This layer may comprise a polymeric material such as polyester, polyvinyl butyral, polyvinyl pyrrolidone and the like. Typically, this layer is of a thickness of less than about 0.6 micron.

The bichromophoric photogenerating pigments employed in the imaging members of the present invention are of the following formulae: ##STR6## wherein Cp represents a coupler group, l, m, n, and o can each be 0, 1, 2, 3, or 4, the sum of l, m, n, and o is from 1 to 8, and M is selected from the group consisting of metals, metal oxides, metal halides, and metal hydroxy compounds. The metal represented by M can be any metal in the periodic table. Examples of suitable metals include Li, Na, Mg, Ca, Fe, Cr, Ni, Co, Cu, Zn, Pb, Cd, Pt, Pd, Mn, Be, Cr, Sn, Ag, Cd, Hg, Sc, and the like. Suitable metal oxides are oxides of any metal in the periodic table, such as TiO, VO, and the like. Suitable metal halides are halides of any metal in the periodic table, such as AlF, AlCl, GaF, GaCl, InF, InCl, InBr, SiF₂, SiCl₂, GeF₂, GeCl₂, SnF₂, SnCl₂, and the like. Suitable metal hydroxy compounds are hydroxides of any metal in the periodic table, such as AlOH, GaOH, InOH, Si(OH)₂, Ge(OH)₂, Sn(OH)₂, and the like. The photogenerating compound can be symmetrical and contain two identical coupler groups or unsymmetrical and contain two different coupler groups. Most coupler groups are aromatic hydrocarbon compounds or heterocyclic compounds with a phenolic hydroxy group, such as 2-naphthol derivatives, although other couplers are also suitable. Examples of suitable coupler groups include ##STR7## wherein X₁ represents --OH, --NR₁ R₂, or --NHSO₂ --R₃ (wherein R₁ and R₂ are hydrogen or a substituted or non-substituted alkyl group and R₃ is a substituted or non-substituted alkyl or a substituted or non-substituted aryl group), Y₁ represents hydrogen, halogen, substituted or non-substituted alkyl groups, substituted or non-substituted alkoxy groups, carboxyl group, sulfo group, substituted or non-substituted sulfamoyl groups, or ##STR8## (wherein R₄ is hydrogen, an alkyl group, a substituted alkyl group, a phenyl group, or a substituted phenyl group, and Y₂ is a cyclic hydrocarbon, a substituted cyclic hydrocarbon, a heterocycle, or a substituted heterocycle, or ##STR9## wherein R₅ represents a cyclic hydrocarbon, a substituted cyclic hydrocarbon, a heterocycle, or a substituted heterocycle and R₆ represents hydrogen, an alkyl group, a substituted alkyl group, a phenyl group, or a substituted phenyl group, and wherein R₅ and R₆ may form a ring with carbons bonded thereto), Z represents a cyclic hydrocarbon or a substituted cyclic hydrocarbon, or a heterocycle or a substituted heterocycle, n is an integer of 1 or 2, m is an integer of 1 or 2, R₇ is a substituted or non-substituted hydrocarbonyl group, R₈ is an alkyl group, a carbamoyl group, a carboxyl group, or a carboxyl ester, Ar₁ is a cyclic hydrocarbon or a substituted cyclic hydrocarbon, R₉ is hydrogen or a substituted or non-substituted hydrocarbonyl group, and Ar₂ is a cyclic hydrocarbon or a substituted cyclic hydrocarbon. Specific examples of the cyclic hydrocarbon ring Z include a benzene ring, a naphthalene group, or the like, as well as heterocycles such as an indole ring, a carbazole ring, a benzofuran ring, and the like. Examples of substituents for the Z ring include halogen atoms such as chlorine, fluorine, iodine, or bromine and the like. Examples of the cyclic hydrocarbon Y₂ or R₅ include phenyl, naphthyl, anthryl, pyrenyl, and the like, as well as heterocycles such as pyridyl, thienyl, furyl, indolyl, benzofuranyl, carbazolyl, dibenzofuranyl, and the like. Examples of the ring formed by bonding R₅ and R₆ include a fluorene ring. Examples of substituents for Y₂ and R₅ or the ring formed by bonding R₅ and R₆ include alkyl groups such as methyl, ethyl, propyl, butyl, or the like, alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, or the like, halogen atoms such as chlorine, fluorine, bromine, iodine, or the like, dialkyl amino groups such as dimethyl amino, diethyl amino, or the like, diaralkyl amino groups such as dibenzyl amino or the like, halomethyl groups such as trifluoromethyl or the like, a nitro group, a cyano group, a carboxyl group or an ester, a hydroxyl group, a sulfonate group such as --SO₃ Na, or the like. Examples of substituents for group R₄ include halogen atoms such as chlorine, fluorine, bromine, or iodine and the like. Examples of hydrocarbonyl groups R₇ and R₉ include alkyl groups such as methyl, ethyl, propyl, butyl, and the like, aralkyl groups such as benzyl and the like, aryl groups such as phenyl, or the like, as well as substituted groups. Examples of substituents for R₇ and R₉ include alkyl groups such as methyl, ethyl, propyl, butyl, or the like, alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, or the like, halogen atoms such as chlorine, bromine, fluorine, iodine, or the like, a hydroxyl group, a nitro group, and the like. Examples of cyclic hydrocarbons Ar₁ and Ar₂ include phenyl, naphthyl, and the like, and examples of substituents for these groups include alkyl groups such as methyl, ethyl, propyl, butyl, or the like, alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, or the like, a nitro group, a halogen group such as chlorine, bromine, fluorine, iodine, or the like, a cyano group, a dialkyl amino group such as dimethyl amino, diethyl amino, or the like.

Specific examples of suitable coupler groups include ##STR10## wherein R is a substituted or non-substituted aliphatic linear or branched hydrocarbon with from 1 to about 20 carbon atoms, preferably with from 1 to about 10 carbon atoms, and Ar is a substituted or non-substituted aromatic hydrocarbon group with from 6 to about 24 carbon atoms or heterocyclic moiety; ##STR11## wherein R is a substituted or non-substituted aliphatic linear or branched hydrocarbon with from 1 to about 20 carbon atoms, preferably with from 1 to about 10 carbon atoms, and Ar is a substituted or non-substituted aromatic hydrocarbon group with from 6 to about 24 carbon atoms or heterocyclic moiety; ##STR12## wherein R is a substituted or non-substituted aliphatic linear or branched hydrocarbon with from 1 to about 20 carbon atoms, preferably with from 1 to about 10 carbon atoms, and Ar is a substituted or non-substituted aromatic hydrocarbon group with from 6 to about 24 carbon atoms or heterocyclic moiety; ##STR13## wherein R is a substituted or non-substituted aliphatic linear or branched hydrocarbon with from 1 to about 20 carbon atoms, preferably with from 1 to about 10 carbon atoms, and Ar is a substituted or non-substituted aromatic hydrocarbon group with from 6 to about 24 carbon atoms or heterocyclic moiety; ##STR14## wherein X is selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, I, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, OH, or other substituents and n is 0, 1, 2, or 3; ##STR15## wherein X and Y are independently selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, I, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, OH, or other substituents, m is 0, 1, 2, 3, or 4, and n is 0, 1, 2, or 3; ##STR16## wherein X is selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, I, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, OH, or other substituents and n is 0, 1, 2, or 3; ##STR17## wherein X is selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, I, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, OH, or other substituents and n is 0, 1, 2, or 3; or any other suitable coupler group. Additional examples of coupler groups are disclosed in, for example, U.S. Pat. No. 4,666,805, the disclosure of which is totally incorporated herein by reference.

Additional examples of suitable couplers include 2-hydroxy-3-naphthanilide, 2-hydroxy-3-naphtho-o-nitroanilide, and 2-hydroxy-3-naphtho-p-nitroanilide, all available from Aldrich Chemical Company; 2-hydroxy-3-naphtho-o-methoxyanilide, 2-hydroxy-3-naphtho-p-methoxyanilide, 2-hydroxy-3-naphtho-o-methylanilide, 2-hydroxy-3-naphtho-p-chloroanilide, 2-hydroxy-3-naphtho-m-nitroanilide, all available from Pfaltz & Bauer Company; Naphthol AS-SG and Naphthol AS-GR, available from Sigma Corporation; 2-hydroxy-3-naphtho-p-methylanilide, 2-hydroxy-3-naphtho-m-methylanilide, 2-hydroxy-3-naphtho-p-fluoroanilide, 2-hydroxy-3-naphtho-o-fluoroanilide, 2-hydroxy-3-naphtho-o-chloroanilide, 2-hydroxy-3-naphtho-m-chloroanilide, 2-hydroxy-3-naphtho-p-bromoanilide, 2-hydroxy-3-naphtho-o-bromoanilide, 2-hydroxy-3-naphtho-p-trifluoromethylanilide, 2-hydroxy-3-naphtho-m-trifluoromethylanilide, 2-hydroxy-3-naphtho-o-ethylanilide, 3-hydroxy-1,8-benzimidazole-naphthalene, N-phenyl-3-hydroxyl-1,8-naphthalimide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-anilide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-p-methylanilide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-o-methylanilide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-o-ethylanilide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-p-fluoroanilide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-m-fluoroanilide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-p-chloroanilide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-m-chloroanilide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-o-chloroanilide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-p-bromoanilide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-o-trifluoromethylanilide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-p-trifluoromethylanilide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-m-nitroanilide, 2-hydroxy-11H-benzo(a)carbazole-3-carbox-p-nitroanilide, 2-hydroxy-8-chloro-11H-benzo(a)carbazole-3-carbox-anilide, 2-hydroxy-8-chloro-11H-benzo(a)carbazole-3-carbox-p-chloroanilide, 2-hydroxy-8-chloro-11H-benzo(a)carbazole-3-carbox-p-fluoroanilide, 2-hydroxy-8-chloro-11H-benzo(a)carbazole-3-carbox-o-methylanilide, and the like. Coupler compounds can also be synthesized by the method disclosed in German Patent 2,410,723, the disclosure of which is totally incorporated herein by reference.

The bichromophoric photogenerating pigments employed in the imaging members of the present invention can be prepared by any suitable process. For example, 4 equivalents of 4-nitrophthalonitrile can be reacted with 1 equivalent of a metal halide in the presence of a catalyst, such as ammonium molybdate, in an inert solvent, such as N-methyl-2-pyrrolidinone, at a temperature of from about 150° C. to about 240° C., as follows: ##STR18## The resulting tetranitro phthalocyanine compound can then be reduced by a reducing agent, such as stannous chloride, sodium sulfide, or the like to form the tetraamino phthalocyanine compound: ##STR19## Subsequently, the tetraamine phthalocyanine compound can be reacted with sodium nitrite in a mineral acid, such as hydrochloric acid, and then with tetrafluoboric acid to form an octazonium salt as follows: ##STR20## Thereafter, the octazonium salt can be reacted with a coupler of choice (2-hydroxy-3-naphthanilide is illustrated) in the presence of a base catalyst, such as sodium acetate, to form a bichromophoric compound of Formula I: ##STR21## The number of azo and coupler groups attached to the phthalocyanine moiety can be varied by varying the phthalonitrile starting material; for example, the phthalonitrile compound can have more than one nitro group, or a mixture of phthalonitrile compounds containing varying numbers of nitro groups can be used as the starting material.

The tetranitro phthalocyanine compound described above may also be prepared from other compounds, such as nitrophthalic acid, nitrophthalic anhydride, nitrophthalimide, nitro-1,3-diiminoisoindole, or the like. Alternatively, the tetraamino phthalocyanine compound can also be prepared from an amino precursor, such as aminophthalic acid, aminophthalic anhydride, aminophthalimide, amino-1,3-diiminoisoindole, aminophthalonitrile, or the like. An example of a process employing an amino precursor for the synthesis of a bichromophoric compound of the present invention is illustrated in a process to prepare a compound of Formula II. For example, about 4 equivalents of 4-aminophthalonitrile can be reacted with about 2 equivalents of a lithium alkoxide in an alcohol to yield the lithium aminophthalocyanine, which upon further reaction with the alcohol produces the metal-free tetraamino phthalocyanine: ##STR22## wherein R is C₂ H₅ OCH₂ CH₂ --. Subsequently, the tetraamine phthalocyanine compound can be reacted with sodium nitrite in a mineral acid, such as hydrochloric acid, and then with hexafluorophosphoric acid to form an octazonium salt as follows: ##STR23## Thereafter, the octazonium salt can be reacted with the coupler of choice (2-hydroxy-3-naphthanilide is illustrated) in the presence of a base catalyst, such as sodium acetate, to form a bichromophoric compound of Formula II: ##STR24## wherein Cp is ##STR25## The number of azo and coupler groups attached to the phthalocyanine moiety can be varied by varying the phthalonitrile starting material; for example, the phthalonitrile compound can have more than one amino group, or a mixture of phthalonitrile compounds containing varying numbers of amino groups can be used as the starting material.

Further information concerning the preparation of nitro phthalocyanine compounds and amino phthalocyanine compounds is disclosed in, for example, "Synthesis and Characterization of Di-disubstituted Phthalocyanines," J. G. Young and W. Onyebuagu, J. Org. Chem., vol. 55, pages 2155 to 2159 (1990); "Direct Pattern Fabrication of Substituted Phthalocyanine Films," H. Tabei et al., Japanese Journal of Applied Physics, vol. 24, no. 9, pages L685 and L686 (1985); "Mossbauer and ESR Spectroscopy of Tetranitro- and Tetraaminophthalocyaninatoiron," N. Kobayashi and H. Konami, Makromol. Chem., Rapid Commun., vol. 10, pages 1 to 4 (1989); "Synthesis and Structural Studies of Metal (II) 4,9,16,23-Phthalocyanine Tetraamines," B. N. Achar et al., Polyhedron, vol. 6, no. 6, pages 1463 to 1467 (1987); "Improved Synthesis of Metal-free Phthalocyanines," P. Brach et al., Journal of Heterocyclic Chemistry, pages 1403 to 1405 (1970); "Infrared Spectra of Nitro- and Amino-substituted Metal Phthalocyanines (MPc)," V. N. Klyuev et al., Khimiya i Khimicheskaya Tekhnologiya, vol. 12, no. 12, pages 1738 to 1741 (1969); and "Dimethylamino-Substituted Phthalocyanines," S. A. Mikhalenko and E. A. Luk'yanets, Zhurnal Obshchei Khimii, vol. 46, no. 9, page 2156 (1976), the disclosures of each of which are totally incorporated herein by reference.

The present invention also encompasses a method of generating images with the photoconductive imaging members disclosed herein. The method comprises the steps of generating an electrostatic latent image on a photoconductive imaging member of the present invention, developing the latent image, and transferring the developed electrostatic image to a substrate. Optionally, the transferred image can be permanently affixed to the substrate. Development of the image may be achieved by a number of methods, such as cascade, touchdown, powder cloud, magnetic brush, and the like. Transfer of the developed image to a substrate may be by any method, including those making use of a corotron or a biased roll. The fixing step may be performed by means of any suitable method, such as flash fusing, heat fusing, pressure fusing, vapor fusing, and the like. Any material used in xerographic copiers and printers may be used as a substrate, such as paper, transparency material, or the like.

Specific embodiments of the invention will now be described in detail. These examples are intended to be illustrative, and the invention is not limited to the materials, conditions, or process parameters set forth in these embodiments. All parts and percentages are by weight unless otherwise indicated.

EXAMPLE I

Copper (II) tetranitrophthalocyanine was prepared as follows. In a 500 milliliter round-bottom flask were mixed 17.25 grams (0.1 mole) of 4-nitrophthalonitrile, 2.5 grams (0.025 mole) of cuprous chloride, a catalytic amount of ammonium molybdate (0.05 gram), and 200 milliliters of 1-methyl-2-pyrrolidinone. The mixture was stirred and heated at about 160° C. for 4 hours, after which the mixture was cooled to room temperature. The blue precipitate thus formed was isolated by filtration with a 600 milliliter fine sintered glass funnel. The blue solid was washed with acetone until the filtrate was light blue in color, and the solid was then transferred to a 750 milliliter flask and boiled with 200 milliliters of 5 percent aqueous hydrochloric acid for 1 hour. Thereafter, the blue solid was collected by filtration and washed with water. The blue solid was then boiled with 200 milliliters of 5 percent aqueous sodium hydroxide, after which the blue solid was collected by filtration and washed with water until the filtrate was neutral. The blue cake was further washed with ethanol and acetone. After vacuum drying, 8.9 grams of copper (II) tetranitrophthalocyanine was obtained (62 percent yield). An infrared spectrum of the product in KBr exhibited peaks as follows: 3100 (C-H), 1615, 1598, 1525, and 1510 (aromatic C--C) cm⁻¹.

EXAMPLE II

Copper (II) tetraaminophthalocyanine was prepared as follows. To 180 milliliters of water was added 6 grams (8 millimoles) of copper (II) tetranitrophthalocyanine to form a dispersion. The dispersion was stirred and 33 grams of sodium sulfide nonahydrate was added to the mixture. The reaction mixture was maintained at 55° C. for 5 hours, during which time the color of the dispersion turned from blue to green. Subsequently, the mixture was cooled to room temperature, and the green solid was isolated by centrifugation and washed twice with water. The green solid was then stirred in 300 milliliters of 1 Normal aqueous hydrochloric acid for 30 minutes, during which time the green solid turned blue. The blue solid was then washed with water and was subsequently suspended in 300 milliliters of 1 Normal aqueous sodium hydroxide for 2 hours. During this time, the blue solid returned to a green color, and afterward was isolated by centrifugation and washed with water until the water was neutral. After vacuum drying, 4.8 grams (95 percent yield) of a dark green solid (copper (II) tetraaminophthalocyanine) was obtained. An infrared spectrum of the product in KBr exhibited peaks as follows: 3440, 3350, 3218 (N--H), 3040 (aromtic C--H), and 1610 (aromatic C--C) cm⁻¹.

EXAMPLE III

Copper (II) tetrakis (1-azo-2-hydroxy-3-naphthanilide) phthalocyanine of the formula ##STR26## wherein Cp is ##STR27## was prepared as follows. In 40 milliliters of concentrated hydrochloric acid was stirred 1.28 grams (2 millimoles) of copper (II) tetraaminophthalocyanine for 2 hours. The resulting blue dispersion was thereafter diluted with 40 milliliters of water and was then cooled to 0° to 5° C. with an ice-water bath. An aqueous solution containing 0.8 gram of sodium nitrite in 2 milliliters of water was then added dropwise to the dispersion. The mixture was allowed to stir for another 30 minutes after the addition was completed, and was then filtered into a pre-cooled filtration flask. Thereafter, 5 milliliters of an aqueous solution containing 60 percent by weight hexafluorophosphoric acid (obtained from Aldrich Chemical Company) was added to the filtrate. After further stirring for 30 minutes, the resulting octazonium product was isolated as the hexafluorophosphate salt by filtration and washing with water, cold methanol, and ether successively, yielding 1.46 grams (58 percent yield) of a green solid. An infrared spectrum of the product in KBr exhibited peaks as follows: 3102 (aromatic C--H), 2270 (--N⁺ .tbd.N), 1602, and 1580 (aromatic C--C) cm⁻¹.

The octazonium salt thus prepared was dissolved in about 50 milliliters of cold dimethyl formamide in a 3-neck 1 liter flask surrounded by an ice-water bath. A coupler solution containing 1.58 grams of 2-hydroxy-3-naphthanilide in 200 milliliters of dimethyl formamide was slowly added to the flask. Subsequently, an aqueous solution containing 2.67 grams of sodium acetate in 40 milliliters of water was added dropwise to the mixture. The temperature of the reaction was maintained at less than 7° C. throughout the reaction. After the addition was completed, the ice bath was removed and the product mixture was allowed to stir at room temperature overnight. The resulting solid product was isolated by filtration and purified by washing twice with 250 milliliter aliquots of water at 80° C., followed by washing three times with 250 milliliter aliquots of dimethyl formamide at 80° C., followed by washing once with 250 milliliters of acetone, and then followed by washing once with 250 milliliters of ether to yield 1.46 grams (42 percent overall yield) of a dark purple copper (II) tetrakis (1-azo-2-hydroxy-3-naphthanilide) phthalocyanine powder with a melting point of over 300° C. An infrared spectrum of the product in KBr exhibited peaks as follows: 3255 (N--H), 3057 (aromatic C--H), 1677 (amide C═O), 1596, and 1542 (aromatic C--C) cm⁻¹.

EXAMPLE IV

Metal-free tetraaminophthalocyanine was prepared as follows. Into a 100 milliliter 3-neck flask equipped with a reflux condenser and a thermometer was added 25 milliliters of 2-ethoxyethanol. The flask was flushed with nitrogen while being cooled to 10° C. Thereafter, 0.21 gram (26 millimoles) of lithium hydride was added to the cooled solution and the temperature of the solution was slowly raised to 35° C. As soon as evolution of hydrogen ceased, 3.0 grams (21 millimoles) of 4-aminophthalonitrile was added to the solution and the mixture was stirred vigorously. The mixture was allowed to reflux for 2 hours, after which a dark green precipitate was formed. The mixture was then cooled to room temperature and poured onto 100 grams of dry ice inside a 500 milliliter beaker. The resulting mixture was allowed to stir overnight, resulting in formation of a green precipitate which was isolated by filtration and washed successively with ethanol, acetone, water, and methanol, followed by Soxhlet extraction with ethanol for 24 hours and air drying of the resulting metal-free tetraaminophthalocyanine product (2.5 grams, 90 percent yield).

Elemental analysis of the product yielded the following results: Calculated for C₃₂ H₂₂ N₁₂ : C 67.0, H 3.8, N 29.3. Actual results: C 67.4, H 3.6, N 29.1.

EXAMPLE V

Metal-free tetrakis (1-azo-2-hydroxy-3-naphthanilide) phthalocyanine of the formula ##STR28## wherein Cp is ##STR29## is prepared as follows. In 40 milliliters of concentrated hydrochloric acid is stirred 2 millimoles of metal-free tetraaminophthalocyanine for 2 hours. The resulting blue dispersion is thereafter diluted with 40 milliliters of water and is then cooled to 0° to 5° C. with an ice-water bath. An aqueous solution containing 0.8 gram of sodium nitrite in 2 milliliters of water is then added dropwise to the dispersion. The mixture is allowed to stir for another 30 minutes after the addition is completed, and is then filtered into a pre-cooled filtration flask. Thereafter, 5 milliliters of an aqueous solution containing 60 percent by weight of hexafluorophosphoric acid (obtained from Aldrich Chemical Company) is added to the filtrate. After further stirring for 30 minutes, the resulting octazonium product is isolated as the hexafluorophosphate salt by filtration and washing with water, cold methanol, and ether successively, yielding a solid.

The octazonium salt thus prepared is dissolved in about 50 milliliters of cold dimethyl formamide in a 3-neck 1 liter flask surrounded by an ice-water bath. A coupler solution containing 1.58 grams of 2-hydroxy-3-naphthanilide in 200 milliliters of dimethyl formamide is slowly added to the flask. Subsequently, an aqueous solution containing 2.67 grams of sodium acetate in 40 milliliters of water is added dropwise to the mixture. The temperature of the reaction is maintained at less than 7° C. throughout the reaction. After the addition is completed, the ice bath is removed and the product mixture is allowed to stir at room temperature overnight. The resulting solid product is isolated by filtration and purified by washing twice with 250 milliliter aliquots of water at 80° C., followed by washing three times with 250 milliliter aliquots of dimethyl formamide at 80° C., followed by washing once with 250 milliliters of acetone, and then followed by washing once with 250 milliliters of ether to yield metal-free tetrakis (1-azo-2-hydroxy-3-naphthanilide) phthalocyanine powder.

EXAMPLE VI

An imaging member is prepared with the photogenerating pigment prepared in Example III as follows. To a 1 ounce amber bottle is added 52.8 milligrams of polyvinyl formal (obtained from Scientific Polymer Products, Inc., formal content 82 percent, acetate content 12 percent, hydroxy content 6 percent) and 10 milliliters of tetrahydrofuran. The bottle is placed on a Wrist Action Shaker and the polymer is dissolved in the tetrahydrofuran. Subsequently, 211.2 milligrams of the photogenerating material prepared in Example III and about 85 grams of steel shots (1/8 inch diameter stainless steel shot) are added to the bottle and the bottle is placed on a Red Devil Paint Conditioner (Model 5100X) and shaken for about 30 minutes. The resulting dispersion is coated onto a 7.5 inch by 10 inch fire-cleaned brush-grained aluminum substrate (obtained from Ron Ink Company) using a Gardner Mechanical Drive with a 6 inch wide Bird Film Applicator (0.5 mil wet gap) inside a humidity controlled glove box. The relative humidity is controlled to less than 25 percent. The resulting charge generator layer is air dried for about 30 minutes and then vacuum dried for about 1 hour at 100° C. to result in a charge generator layer with a thickness of about 0.4 micron.

The above charge generator layer is then overcoated with a charge transport layer prepared as follows. A solution containing 4.2 grams of Makrolon®, a polycarbonate resin obtained from Larbensabricken Bayer A.G., 2.8 grams of N,N'-bis(3"-methylphenyl)-1,1'-biphenyl-4,4'-diamine perpared as disclosed in U.S. Pat. No. 4,265,990, the disclosure of which is totally incorporated herein by reference, is prepared by dissolving the above materials in 31 milliliters of methylene chloride inside a 2 ounce amber bottle. The transport layer is obtained by coating the solution onto the charge generator layer using a 3.5 inch wide, 5 mil wet gap Bird Film Applicator, resulting in a transport layer about 25 microns thick. The resulting photoconductive device is air dried for about 1 hour and vacuum dried at 100° C. for about 16 hours before electrical testing.

The photoconductive imaging member thus prepared is then incorporated into a xerographic imaging test fixture. Latent images are formed on the member and developed with a toner comprising 88 percent by weight styrene/n-butylmethacrylate copolymer resin, 8 percent by weight Regal® 330 carbon black, and 2 percent by weight distearyl dimethyl ammonium methyl sulfate. The resulting images are of excellent resolution and high quality.

EXAMPLE VII

An imaging member is prepared with the photogenerating pigment prepared in Example V by repeating the procedure of Example VI, with the exception that metal-free tetrakis (1-azo-2-hydroxy-3-naphthanilide) phthalocyanine is substituted for copper (II) tetrakis (1-azo-2-hydroxy-3-naphthanilide) phthalocyanine. The photoconductive imaging member thus prepared is then incorporated into a xerographic imaging test fixture. Latent images are formed on the member and developed with a toner comprising 88 percent by weight styrene/n-butylmethacrylate copolymer resin, 8 percent by weight Regal® 330 carbon black, and 2 percent by weight distearyl dimethyl ammonium methyl sulfate. The resulting images are of excellent resolution and high quality.

Other embodiments and modifications of the present invention may occur to those skilled in the art subsequent to a review of the information presented herein; these embodiments and modifications, as well as equivalents thereof, are also included within the scope of this invention. 

What is claimed is:
 1. An imaging member which comprises a conductive substrate and a photogenerator layer containing a photogenerating compound selected from the group consisting of: ##STR30## and mixtures thereof, wherein Cp represents a coupler group, l, m, n, and o can each be 0, 1, 2, 3, or 4, the sum of l, m, n, and o is from 1 to 8, and M is selected from the group consisting of metals, metal oxides, metal halides, and metal hydroxy compounds.
 2. An imaging member according to claim 1 also containing a charge transport layer.
 3. An imaging member according to claim 2 wherein the photogenerator layer is situated between the conductive substrate and the charge transport layer.
 4. An imaging member according to claim 2 wherein the charge transport layer is situated between the conductive substrate and the photogenerator layer.
 5. An imaging member according to claim 1 wherein the conductive substrate is a metal.
 6. An imaging member according to claim 1 wherein the conductive substrate is aluminum.
 7. An imaging member according to claim 1 wherein the photogenerator layer has a thickness of from about 0.05 to about 10 microns.
 8. An imaging member according to claim 1 wherein the photogenerating compound is dispersed in a resinous binder in an amount of from about 5 percent by weight to about 95 percent by weight.
 9. An imaging member according to claim 8 wherein the resinous binder is selected from the group consisting of polyesters, polyvinyl butyrals, polycarbonates, and polyvinyl formals.
 10. An imaging member according to claim 1 wherein the charge transport layer comprises an aryl amine compound.
 11. An imaging member according to claim 10 wherein the aryl amine is of the formula: ##STR31## wherein X is selected from the group consisting of alkyl and halogen and wherein the aryl amine is dispersed in a highly insulating and transparent organic resinous binder.
 12. An imaging member according to claim 11 wherein X is selected from the group consisting of ortho (CH₃), meta (CH₃), para (CH₃), ortho (CI), meta (CI), and para (CI).
 13. An imaging member according to claim 11 wherein the resinous binder is selected from the group consisting of polycarbonates and polystyrenes.
 14. An imaging member according to claim 1 wherein the photogenerating compound is of the formula ##STR32## wherein Cp represents a coupler group, l, m, n, and o can each be 0, 1, 2, 3, or 4, the sum of l, m, n, and o is from 1 to 8, and M is selected from the group consisting of metals, metal oxides, metal halides, and metal hydroxy compounds.
 15. An imaging member according to claim 1 wherein the photogenerating compound is of the formula ##STR33## wherein Cp represents a coupler group, l, m, n, and o can each be 0, 1, 2, 3, or 4, and the sum of l, m, n, and o is from 1 to
 8. 16. An imaging member according to claim 1, 14, or 15 wherein the coupler group is selected from the group consisting of ##STR34## wherein X₁ is selected from the group consisting of --OH, --NR₁ R₂, and --NHSO₂ --R₃ (wherein R₁ and R₂ are selected from the group consisting of hydrogen, substituted alkyl groups, and non-substituted alkyl groups, and R₃ is selected from the group consisting of substituted alkyl groups, non-substituted alkyl groups, substituted aryl groups, and non-substituted aryl groups), Y₁ is selected from the group consisting of hydrogen, halogens, substituted alkyl groups, non-substituted alkyl groups, substituted alkoxy groups, non-substituted alkoxy groups, carboxyl groups, sulfo groups, substituted sulfamoyl groups, non-substituted sulfamoyl groups, and ##STR35## (wherein R₄ is selected from the group consisting of hydrogen, alkyl groups, substituted alkyl groups, phenyl groups, and a substituted phenyl groups, and Y₂ is selected from the group consisting of cyclic hydrocarbons, substituted cyclic hydrocarbons, heterocycles, and substituted heterocycles, and ##STR36## wherein R₅ is selected from the group consisting of cyclic hydrocarbons, substituted cyclic hydrocarbons, heterocycles, and substituted heterocycles, and R₆ is selected from the group consisting of hydrogen, alkyl groups, substituted alkyl groups, phenyl groups, and substituted phenyl groups, and wherein R₅ and R₆ may form a ring, Z is selected from the group consisting of cyclic hydrocarbons, substituted cyclic hydrocarbons, heterocycles, and substituted heterocycles, n is an integer of 1 or 2, m is an integer of 1 or 2, R₇ is selected from the group consisting of substituted hydrocarbonyl groups and non-substituted hydrocarbonyl groups, R₈ is selected from the group consisting of alkyl groups, carbamoyl groups, carboxyl groups, and carboxyl esters, Ar₁ is selected from the group consisting of cyclic hydrocarbons and substituted cyclic hydrocarbons, R₉ is selected from the group consisting of hydrogen, substituted hydrocarbonyl groups, and non-substituted hydrocarbonyl groups, and Ar₂ is selected from the group consisting of cyclic hydrocarbons and substituted cyclic hydrocarbons.
 17. An imaging member according to claim 1, 14, or 15 wherein the coupler group is selected from the group consisting of ##STR37## wherein R is selected from the group consisting of substituted and non-substituted aliphatic hydrocarbon with from 1 to about 20 carbon atoms and Ar is selected from the group consisting of substituted and non-substituted aromatic hydrocarbon group with from 6 to about 24 carbon atoms and substituted and non-substituted heterocyclic moieties; ##STR38## wherein R is selected from the group consisting of substituted and non-substituted aliphatic hydrocarbon with from 1 to about 20 carbon atoms and Ar is selected from the group consisting of substituted and non-substituted aromatic hydrocarbon group with from 6 to about 24 carbon atoms and substituted and non-substituted heterocyclic moieties; ##STR39## wherein R is selected from the group consisting of substituted and non-substituted aliphatic hydrocarbon with from 1 to about 20 carbon atoms and Ar is selected from the group consisting of substituted and non-substituted aromatic hydrocarbon group with from 6 to about 24 carbon atoms and substituted and non-substituted heterocyclic moieties; ##STR40## wherein R is selected from the group consisting of substituted and non-substituted aliphatic hydrocarbon with from 1 to about 20 carbon atoms and Ar is selected from the group consisting of substituted and non-substituted aromatic hydrocarbon group with from 6 to about 24 carbon atoms and substituted and non-substituted heterocyclic moieties; ##STR41## wherein X is selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, I, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, and OH and n is 0, 1, 2, or 3; ##STR42## wherein X and Y are independently selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, I, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, and OH, m is 0, 1, 2, 3, or 4, and n is 0, 1, 2, or 3; ##STR43## wherein X is selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, I, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, and OH and n is 0, 1, 2, or 3; and ##STR44## wherein X is selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, I, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, and OH and n is 0, 1, 2, or
 3. 18. A method of imaging which comprises generating an electrostatic latent image on an imaging member of claim 1, developing the latent image, and transferring the developed electrostatic image to a suitable substrate.
 19. A photogenerating compound of the formula ##STR45## wherein Cp represents a coupler group, l, m, n, and o can each be 0, 1, 2, 3, or 4, the sum of l, m, n, and o is from 1 to 8, and M is selected from the group consisting of metals, metal oxides, metal halides, and metal hydroxy compounds.
 20. A photogenerating compound of the formula ##STR46## wherein Cp represents a coupler group, l, m, n, and o can each be 0, 1, 2, 3, or 4, and the sum of l, m, n, and o is from 1 to
 8. 21. A photogenerating compound according to claim 19 or 20 wherein the coupler group is selected from the group consisting of ##STR47## wherein X₁ is selected from the group consisting of --OH, --NR₁ R₂, and --NHSO₂ --R₃ (wherein R₁ and R₂ are selected from the group consisting of hydrogen, substituted alkyl groups, and non-substituted alkyl groups, and R₃ is selected from the group consisting of substituted alkyl groups, non-substituted alkyl groups, substituted aryl groups, and non-substituted aryl groups), Y₁ is selected from the group consisting of hydrogen, halogens, substituted alkyl groups, non-substituted alkyl groups, substituted alkoxy groups, non-substituted alkoxy groups, carboxyl groups, sulfo groups, substituted sulfamoyl groups, non-substituted sulfamoyl groups, and ##STR48## wherein R₄ is selected from the group consisting of hydrogen, alkyl groups, substituted alkyl groups, phenyl groups, and a substituted phenyl groups, and Y₂ is selected from the group consisting of cyclic hydrocarbons, substituted cyclic hydrocarbons, heterocycles, and substituted heterocycles, and ##STR49## wherein R₅ is selected from the group consisting of cyclic hydrocarbons, substituted cyclic hydrocarbons, heterocycles, and substituted heterocycles and R₆ is selected from the group consisting of hydrogen, alkyl groups, substituted alkyl groups, phenyl groups, and substituted phenyl groups, and wherein R₅ and R₆ may form a ring, Z is selected from the group consisting of cyclic hydrocarbons, substituted cyclic hydrocarbons, heterocycles, and substituted heterocycles, n is an integer of 1 or 2, m is an integer of 1 or 2, R₇ is selected from the group consisting of substituted hydrocarbonyl groups and non-substituted hydrocarbonyl groups, R₈ is selected from the group consisting of alkyl groups, carbamoyl groups, carboxyl groups, and carboxyl esters, Ar₁ is selected from the group consisting of cyclic hydrocarbons and substituted cyclic hydrocarbons, R₉ is selected from the group consisting of hydrogen, substituted hydrocarbonyl groups, and non-substituted hydrocarbonyl groups, and Ar₂ is selected from the group consisting of cyclic hydrocarbons and substituted cyclic hydrocarbons.
 22. A photogenerating compound according to claim 19 or 20 wherein the coupler group is selected from the group consisting of ##STR50## wherein R is selected from the group consisting of substituted and non-substituted aliphatic hydrocarbon with from 1 to about 20 carbon atoms and Ar is selected from the group consisting of substituted and non-substituted aromatic hydrocarbon group with from 6 to about 24 carbon atoms and substituted and non-substituted heterocyclic moieties; ##STR51## wherein R is selected from the group consisting of substituted and non-substituted aliphatic hydrocarbon with from 1 to about 20 carbon atoms and Ar is selected from the group consisting of substituted and non-substituted aromatic hydrocarbon group with from 6 to about 24 carbon atoms and substituted and non-substituted heterocyclic moieties; ##STR52## wherein R is selected from the group consisting of substituted and non-substituted aliphatic hydrocarbon with from 1 to about 20 carbon atoms and Ar is selected from the group consisting of substituted and non-substituted aromatic hydrocarbon group with from 6 to about 24 carbon atoms and substituted and non-substituted heterocyclic moieties; ##STR53## wherein R is selected from the group consisting of substituted and non-substituted aliphatic hydrocarbon with from 1 to about 20 carbon atoms and Ar is selected from the group consisting of substituted and non-substituted aromatic hydrocarbon group with from 6 to about 24 carbon atoms and substituted and non-substituted heterocyclic moieties; ##STR54## wherein X is selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, I, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, and OH and n is 0, 1, 2, or 3; ##STR55## wherein X and Y are independently selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, I, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, and OH, m is 0, 1, 2, 3, or 4, and n is 0, 1, 2, or 3; ##STR56## wherein X is selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, I, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, and OH and n is 0, 1, 2, or 3; and ##STR57## wherein X is selected from the group consisting of H, CH₃, C₂ H₅, C₃ H₇, Cl, F, Br, I, NO₂, CF₃, OCH₃, OC₂ H₅, CN, NH₂, and OH and n is 0, 1, 2, or
 3. 